Marine Vessel Hybrid Propulsion System

ABSTRACT

A marine propulsion system is configured to allow many different combinations and interconnections between three internal combustion engines, three generators, two motors, two clutches, two marine propulsion devices, and an electrical storage device. By appropriately interconnecting these devices in advantageous combinations, energy consumption can be reduced, operational efficiency of the engine can be improved, and redundancy can be provided in the event that one or more components are disabled.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a marine vessel propulsion system and, more particularly, to a hybrid system that utilizes internal combustion engines, electric generators and motors, and an electrical storage device.

2. Background

Those skilled in the art of marine vessels are familiar with various types of propulsion systems, including those which use internal combustion engines and electric motors. Hybrid vehicles provide alternative sources of power which can be selected, as a function of conditions or circumstances, to conserve energy and improve efficiency.

U.S. Pat. No. 6,396,161, which issued to Crecelius et al. on May 28, 2002, describes an integrated starter alternator troller. A marine integrated starter alternative troller device (ISAT) includes a stator portion and a rotor portion connected to a driveshaft. The ISAT is incorporated into an engine assembly power train which includes an internal combustion engine having a crankshaft connected to an electric clutch. The electric clutch is operable to connect or disconnect the driveshaft and the crankshaft. Thus, the ISAT may be connected to or disconnected from the crankshaft of the internal combustion engine. When connected to the engine by the electric clutch, the ISAT device is operable to receive electric power from a battery and act as a cranking motor to provide starting torque to the internal combustion engine. The ISAT may also be driven by the internal combustion engine and act as a generator to provide power to recharge the battery or drive other electrical devices.

U.S. Pat. No. 6,846,208, which issued to Goldmeer et al. on Jan. 25, 2005, describes a wave rotor based power and propulsion generation system for a marine vessel. A hybrid power and propulsion generation system for a marine vessel is provided that combines a fuel cell with a wave rotor/combustor. A wave rotor that uses gas dynamics (shock and expansion) processes within rotating passages, using a hydrogen and oxygen supply in fluid communication with the wave rotor, is combined with a regenerative fuel cell for power generation for an underwater vessel.

U.S. Pat. No. 6,857,918, which issued to Lebreux et al. on Feb. 22, 2005, describes a personal watercraft having a hybrid power source. A hybrid fuel/electric powered watercraft includes an electronic turning machine (ETM), and internal combustion engine, and a propulsion system, which are operatively connected to each other, preferably via one or more clutches. An electronic control unit (ECU) controls the ETM, clutches, and engine. At low speeds, the ECU disengages at least one clutch and solely uses the ETM to power the propulsion unit and propel the watercraft. At high speeds, the ECU engages the clutch and uses both the engine and the ETM or just the engine to power the propulsion system.

U.S. Pat. No. 6,912,967, which issued to Oats et al. on Jul. 5, 2005, describes a hybrid watercraft. It is steered under power by water jet propulsion and utilizes a water intake ramp in its hull to create a nozzle-like effect to accelerate water loading to the jet pump through a ventral water inlet when under power. The hull has a pair of longitudinal stabilizers that form a tunnel in which the ramp is located. A canopy, which can be removable, encloses a passenger compartment with a steering wheel and one or more passenger seats.

U.S. patent application Ser. No. 11/455,871, which was filed by Jones on Jun. 19, 2006, describes a dual hybrid propulsion system. The system can help curb the fuel consumption rate of trucks/large motor vehicles without reducing peak power outputs. A vehicle having a dual series hybrid power system includes two liquid fueled internal combustion engines, each engine having a generator directly connected.

U.S. Pat. No. 7,241,192, which issued to Andersen et al. on Jul. 10, 2007, describes a hybrid ship propulsion system. The system includes a main diesel engine for driving the marine turbine and an electric motor. The electric motor has a nominal output that constitutes at least 20% of the nominal output of the main diesel engine. The electric motor remains continuously switched on and maintains, together with a variable-pitch propeller, the main diesel engine at a favorable operating point. The combination of the main diesel engine and the electric motor also allows for a more economical design or operation of the propulsion system.

U.S. patent application Ser. No. 11/841,652, which was filed on Aug. 20, 2007, by Mizokawa describes a watercraft propulsion system and operating method. The system has a control lever for giving instructions regarding operating mode and output power from a source of driving force. A controller sets a propeller driving mode according to instructions given from the control lever. In an embodiment, an electric motor and an engine are included in the propulsion system, and the controller simultaneously controls both the engine and motor based on inputs from the control lever and sensed conditions.

U.S. Pat. No. 7,381,107, which issued to Ishikawa et al. on Jun. 3, 2008, describes an outboard motor equipped with an internal combustion engine and electric motor as selective sources of power for driving the propeller and further provided with the first output shaft connected to the engine for transmitting its output to the propeller and the second output shaft connected to the motor for transmitting its output to the propeller, the first and second output shafts being disposed coaxially, so that the amount of space required for installing the shafts is smaller by the length of their coaxial portion relative to the prior art in which the shafts are simply connected in tandem. As a result, the size and weight of the outboard motors can be reduced, thereby enhancing its ease of operation and portability.

The patents described above are hereby expressly incorporated by reference in the description of the present invention.

It would be significantly beneficial if a marine propulsion system could be provided which allows a marine vessel to be selectively powered by internal combustion engines or electric motors in order to conserve energy by more efficiently using the internal combustion engines. It would also be beneficial if advantageous redundancy could be provided in the event that one or both of the primary internal combustion engines becomes disabled.

SUMMARY OF THE INVENTION

A marine vessel, made in accordance with a preferred embodiment of the present invention, comprises first and second engines, first and second marine propulsion devices, first and second motors, and first and second generators. The first and second engines are connectable in torque transmitting association with the first and second marine propulsion devices, respectively. The first and second motors are connectable in torque transmitting association with the first and second marine propulsion devices, respectively. The first and second engines are connectable in torque transmitting association with the first and second generators, respectively. In a particularly preferred embodiment of the present invention, it further comprises an electrical storage device which is connectable in electrical communication with the first and second generators. The electrical storage device is connectable in electrical communication with the first and second motors. The electrical storage device comprises a battery which can, in turn, comprise a plurality of dry cells or wet cells.

In a preferred embodiment of the present invention, the electrical storage device is configured to receive electric current from the first and second generators. It is configured to provide electric current to the first and second motors. In addition, the electrical storage device is configured to provide electric current to a house load of the marine vessel.

In a particularly preferred embodiment of the present invention, it further comprises a third engine and a third generator. The third engine is connectable in torque transmitting association with the third generator and the electrical storage device is connectable in electrical communication with the third generator.

In a preferred embodiment of the present invention, a first motor-generator device comprises the first generator and the first motor and a second motor-generator device comprises the second generator and the second motor. In a preferred embodiment of the present invention, it can further comprise first and second clutches which are configured to selectively connect the first and second engines, respectively, in torque transmitting association with the first and second marine propulsion devices.

In one configuration of the present invention, the first engine is connected in torque transmitting association with both the first marine propulsion device and the first generator and the second motor is simultaneously connected in torque transmitting association with the second marine propulsion device. The second engine is disconnected from torque transmitting association with the second marine propulsion device.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more fully and completely understood from a reading of the description of the preferred embodiment in conjunction with the drawings, in which:

FIGS. 1-12 show various interconnection schemes using the basic components of a preferred embodiment of the present invention;

FIG. 13 schematically represents a marine vessel with the components of a preferred embodiment of the present invention;

FIG. 14 is generally similar to FIG. 13 but with several additional components and hardware which facilitates the various interconnections; and

FIG. 15 is a section view of a motor-generator used in a preferred embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Throughout the description of the preferred embodiment of the present invention, like components will be identified by like reference numerals.

FIGS. 1-12 are highly schematic representations of various modes of use and configurations of a preferred embodiment of the present invention. FIG. 13 shows the basic components of a marine propulsion system made in accordance with a preferred embodiment of the present invention and FIG. 14 is generally similar to FIG. 13, but with certain additional components illustrated. FIG. 15 is a simplified section view of a motor-generator, with a clutch, that is used in a preferred embodiment of the present invention. It should be understood that, as an alternative to the clutch, a gear shift can be used to drive a generator with a shaft that, in many different embodiments of the present invention, rotates about an axis that is generally parallel to the driveshaft of an engine. The particular type of clutch or gear set is not limiting to the present invention.

With reference to FIG. 13, dashed box 10 represents a marine vessel which incorporates a first engine 11, a second engine 12, and a third engine 13. A first marine propulsion device 21 and a second marine propulsion device 22 are attached to the marine vessel 10. The marine propulsion devices can be sterndrives or pod-type drive units that extend downwardly through the hull of the marine vessel 10. Alternatively, inboard or V-type propulsion system arrangements can be used in conjunction with the concepts of the present invention. It should be understood that the particular type of marine propulsion device, 21 or 22, is not limiting to the present invention. First and second motor-generators, 31 and 32, each comprise a motor and a generator. The motors are connectable in torque transmitting association with an associated one of the two marine propulsion devices, 21 and 22. The generators are connectable in torque transmitting association with an associated one of the first and second engines, 11 and 12. An electrical storage device 40 is connectable in electrical communication with the first and second generators for recharging the electrical storage device. A third generator 43 is connectable in torque transmitting association with the third engine 13. The house load 46 of the marine vessel 10 is represented by a box in FIG. 13, but it should be understood that this house load 46 comprises the various electrical devices of the vessel. For example, lights, navigation equipment, air conditioning, and other electrical devices on the marine vessel 10 receive their power from the electrical storage device 40.

FIG. 14 is generally similar to FIG. 13, but with certain details and additional components illustrated. As an example, output shafts, 51 and 52, are shown extending from their respective first and second engines, 11 and 12. Driveshafts, 61 and 62, are shown connected between the first and second motor-generators, 31 and 32, and the associated marine propulsion devices, 21 and 22. In addition, first and second clutches, 71 and 72, are shown associated with the first and second motor-generators, 31 and 32. As will be described below, the clutches allow the output shafts, 51 and 52, to be disconnected from the driveshafts, 61 and 62, in order to allow the motors of the first and second motor-generators, 31 and 32, to provide propulsive power to the first and second marine propulsion devices without the associated engines, 11 and 12, being connected to the motor-generators. Box 76 represents the electrical components used to provide the necessary interconnection between the third generator 43 and the electrical storage device 40. In certain embodiments of the present invention, device 76 would include a rectifier that converts the AC power from the third generator 43 to DC power that is usable in recharging the electrical storage device 40, which can comprise a plurality of batteries. Similarly, the two boxes shown in FIG. 14 and identified by reference numerals 81 and 82 provide the electronic components necessary to receive AC current from the first and second motor-generators, 31 and 32, and provide DC current for recharging the electrical storage device 40. Those skilled in the art of propulsion systems and electrical systems are aware that other electrical components, including switches, filters, fuses, regulators and other devices would typically be provided in order to perform normal operations related to the control and switching of electric power between the various devices shown in FIGS. 13 and 14.

FIG. 15 is a simplified section view of the first motor-generator 31 and its associated first clutch 71. For purposes of simplicity, the first clutch 71 is illustrated as having a first plurality of plates 91 attached to the driveshaft 61 and a second plurality of plates 92 attached to the output shaft 51 from the first engine 11, as described above in conjunction with FIG. 14. When the first clutch 71 is energized, torque is transmitted between the first output shaft 51 and the first driveshaft 61. When the first clutch 71 is deenergized, the first driveshaft 61 is disconnected from the first output shaft 51 and first engine 11. When the clutch is deenergized, the first motor-generator 31, connected as a motor, can drive the first marine propulsion device 21 without involvement of the first engine 1 1.

With continued reference to FIG. 15, the first motor-generator 31 comprises a stator portion 94 and a rotor portion 96. Depending on the electrical connections between the motor-generator and other components, it can operate as the first generator to provide electric current to the electrical storage device 40 or, alternatively, as the first motor to provide torque to the first marine propulsion device 21. It should be understood that although the first clutch 71 in FIG. 15 is illustrated as comprising a plurality of disks, or plates, many different types of clutches can be used to perform the function described above. Any type of clutch that is capable of connecting and disconnecting the associated engine, 11 or 12, with the associated motor-generator, 31 or 32, can be used in conjunction with the preferred embodiment of the present invention.

The system components described above in conjunction with FIGS. 13-15, can be used in various combinations in order to provide enhanced flexibility, energy conservation, and improved redundancy of the marine propulsion system. In conjunction with FIGS. 1-12, numerous modes of operation and interconnection will be described for various embodiments of the present invention. It should be understood that, in relation to certain of these embodiments, the description may refer to one (e.g. the first or the second) of the engines, motors, generators, or marine propulsion devices, but that description could alternatively apply to the other of the various cares of these devices.

FIG. 1 illustrates one of the simplest applications of a preferred embodiment of the present invention. It shows the electrical storage device 40 connected to the house load 46 of the marine vessel 10. This connection would typically be used when the marine vessel is stationary, the electrical storage device 40 is fully charged, and the operator of the marine vessel 10 is utilizing some electrical systems of the marine vessel, such as lights, an entertainment center, or air conditioning. The power flow, from the electrical storage device 40 to the house load 46 is represented by arrow 101.

FIG. 2 is generally similar to FIG. 1, but represents the condition where the electrical storage device 40 is not fully charged. In that circumstance, the third engine 13 can be used to drive the third generator 43 and electric power is provided, as represented by arrow 102, to the electrical storage device 40. The power needed for the house load 46 continues to be provided, as represented by arrow 101, by the electrical storage device 40 which can comprise a plurality of wet or dry cells. It should be understood that electric power can be provided for the house load 46 in alternative arrangements. For example, with reference to FIGS. 2 and 13, the engine 11 can be used to drive the generator 57, which will be described in greater detail below, and that generator can be used to maintain the charge on the electrical storage device 40 which, in turn, provides electrical power for the house load 46. Of course, it should be understood that the symmetrical arrangement, where engine 12 drives generator 58, which will be described in greater detail below, to provide electrical power to maintain the charge on the electrical storage device 40 which provides the electrical power for the house load 46.

FIG. 3 represents a condition where the marine vessel 10 is being driven by the first and second motors, 53 and 54, of the first and second motor-generators, 31 and 32, respectively. None of the engines are used in this mode of operation. Electric power is provided by the batteries of the electrical storage device 40 which also provides power to the house load 46. The first and second motors, 53 and 54, receive electric power from the electrical storage device 40 as represented by arrows 103 and 104. The motors, in turn, provide torque to the first and second marine propulsion devices, 21 and 22, as represented by arrows 105 and 106. The embodiment shown in FIG. 3 would typically be used during low speed operation, such as maneuvering within a marina or docking the marine vessel at a pier, at a time when the electrical storage device 40 is fully charged or nearly fully charged. Those skilled in the art of electrical systems are aware of the fact that the electrical storage device 40 need not always be brought to a full charge. Typically, it is sufficient if the electrical storage device 40 is maintained at a charge level of 20% or more.

FIG. 4 illustrates a mode of operation that is generally similar to FIG. 3, but with the third engine 13 used to provide charging current, with the third generator 43 as represented by arrow 102, to the electrical storage device 40. The embodiment illustrated in FIG. 4 would be used in circumstances generally similar to those described above in conjunction with FIG. 3, but when the electrical storage device 40 is not fully charged. Typically, the level of charge of the electrical storage device would be compared to a predefined magnitude and, when the charge of the electrical storage device 40 falls below that predefined magnitude, the third engine 13 would be activated to increase the charge of the battery system. During this process, current is provided by the electrical storage device 40 to the motors, 53 and 54, of the motor-generators, 31 and 32, and the first and second motors would provide torque to drive the first and second marine propulsion devices, 21 and 22.

With reference to FIGS. 3, 4, 13 and 14, it should be understood that although the first and second engines, 11 and 12, and first and second clutches, 71 and 72, are not illustrated in FIGS. 3 and 4, the first and second clutches are deenergized in order to disconnect the output shafts, 51 and 52, from the driveshafts, 61 and 62, during the use of the present invention in the modes illustrated in FIGS. 3 and 4. This disconnects the engines from the first and second motors, 53 and 54, so that they do not provide resistance as the motors are driving the first and second marine propulsion devices, 21 and 22.

With continued reference to FIG. 4, it should be understood that the motors, 53 and 54, can be provided with electric energy directly from generator 43 or, alternatively, with power provided both by the generator 43 and the electrical storage device 40 connected in parallel.

FIG. 5 illustrates an embodiment of the present invention which uses the first engine 11 to provide torque to drive the first marine propulsion device 21, as illustrated by arrow 110. This torque is provided by the connection between an output shaft 51 of the engine 11 and a driveshaft 61, as described above in conjunction with FIG. 14, which is accomplished by energizing the first clutch 71 as described above in conjunction with FIGS. 14 and 15. The torque provided to the propeller of the first marine propulsion device 21 is controlled by controlling the operating speed of the first engine 11. The first motor-generator 31 is connected electrically in a manner which causes it to operate as a first generator 57 to provide electric power to the electrical storage device 40, as represented by arrow 112. Torque is provided by the first engine 11, as represented by arrow 111, to drive the rotor 96 of the first motor-generator 31 as described above in conjunction with FIG. 15. In effect, the first engine 11 provides mechanical torque to drive the first marine propulsion device 21 and to drive the first generator 57 of the first motor-generator 31. The second motor-generator 32 is connected electrically to operate as a motor and the second clutch 72 (not illustrated in FIG. 5) is deenergized to disconnect the second engine 12 from the second driveshaft 62. Electric energy is provided by the electrical storage device 40 to the second motor 54, as represented by arrow 104, and the second motor provides torque to the second marine propulsion device 22 as represented by arrow 106. The mode of operation illustrated in FIG. 5 results in the first marine propulsion device 21 being driven by the first engine 11 while the second marine propulsion device 22 is driven by the second motor 52. As described above, the first and second motor-generators, 31 and 32, can be operated as generators to charge the batteries of the electrical storage device 40 or, alternatively, as motors to provide mechanical torque to the first and second marine propulsion devices, 21 and 22.

With continued reference to FIGS. 5 and 14, it can be seen that the mode of operation illustrated in FIG. 5 is particularly beneficial in two particularly circumstances. First, if the second engine 12 experiences a malfunction, either with the engine itself or its associated clutch, the marine vessel 10 can still be operated satisfactorily under these emergency conditions. Another condition under which the mode shown in FIG. 5 can be particularly advantageous is when the marine vessel 10 is operated at relatively low speeds that could require the first and second engines, if both are operated simultaneously, to be run at inefficient speeds. As those skilled in the art of engine operation know, the efficiency of an internal combustion engine is significantly improved if it is operated at particular engine speeds. If one engine is used at a higher speed to drive a higher load, than if two engines shared the load, the overall operation of the propulsion system experiences improved efficiency. The situation illustrated in FIG. 5 allows this improvement to be realized.

With continued reference to FIG. 5, it should be understood that the arrangement and interconnection of components is exemplary and could be reversed. In other words, although the first engine 11 on the port side of the marine vessel 10 is used as the prime mover, with the second engine 12 being disconnected by the second clutch 72, the reverse could also be applicable. In other words, the second engine 12 could be used to provide torque to the second generator of the second motor-generator 32 which, in turn, would provide charging current to the electrical storage device 40. The electrical storage device would, in turn, provide electric power to the first motor 53 which would provide torque to the first marine propulsion device 21. In other words, the application shown in FIG. 5 could be reversed symmetrically to achieve the same goals. This would be particularly helpful if the first engine 11 experienced a malfunction. Alternatively, the use of the second engine 12 with the deactivation of the first engine 11 would result in similar improvements in efficiency as described above. FIG. 6 is similar to FIG. 5, but with the additional use of the third engine 13 and third generator 43 to provide additional electric power. As in the mode illustrated in FIG. 5, the first motor-generator 31 is operated as a generator and the second motor-generator 32 is operated as a motor.

With continued reference to FIGS. 5 and 6, those skilled in the art of electrical systems are aware that power can be provided from the generator 57 to the motor 54 directly and without involvement of the electrical storage device 40. In FIG. 5, an appropriate device 210 receives alternating current from generator 57, as represented by arrow 212, and provides alternating current to the motor 54 as represented by arrow 214. The device 210 can comprise a rectifier, regulator, and inverter. Various components are known to those skilled in the art which enable a generator 57 to provide power to a motor 54 and provide the necessary frequency control and regulation for that purpose. A similar system can be used in FIG. 6 although it is not specifically illustrated.

FIG. 7 illustrates a mode of operation of the present invention in which the first and second engines, 11 and 12, are used to provide mechanical torque to their associated marine propulsion devices, 21 and 22, as represented by arrows 110 and 114. The torque is provided by connecting the first and second clutches, 71 and 72, as described above in conjunction with FIG. 14, in torque transmitting association between the output shafts, 51 and 52, and the driveshafts, 61 and 62, respectively. The electrical storage device 40 is used to provide electric power to the house load 46. The mode of operation shown in FIG. 7 is relatively conventional in that the engines are used to provide mechanical torque to the marine propulsion devices in a manner that is well known to those skilled in the art and the electrical storage device 40 is used to provide electric power to the house load.

In FIG. 8, the first and second engines are used to provide mechanical torque to the first and second marine propulsion devices, as represented by arrows 110 and 114 and the electrical storage device 40 is used to provide electric power to the house load 46 as represented by arrow 101. However, the first and second engines are also used to provide torque to drive the first and second generators, 57 and 58, of the first and second motor-generators, 31 and 32, as represented by arrows 111 and 121. The generators can then provide electric power to recharge or maintain the charge of the electrical storage device 40 as represented by arrows 112 and 122. In the arrangement illustrated in FIG. 8, the first and second marine propulsion devices receive all required torque from the connection between the output shafts, 51 and 52, and the driveshafts, 61 and 62, respectively, which are the result of the energerization of the first and second clutches, 71 and 72, as described above in conjunction with FIG. 14. The first and second engines also provide the required torque to drive the generators, 57 and 58, in order to maintain the charge of the electrical storage device 40 which provides power to the house load 46.

FIG. 9 is generally similar to FIG. 8, but with the additional use of the third engine 13 and third generator 43 to provide additional electric power to the electrical storage device 40. The mode of operation illustrated in FIG. 9 would typically be used when the marine vessel 10 is operated at relatively high speed and the house load 46 is higher than normal. In these circumstances, maintaining the level of charge of the electrical storage device 40 with only the first and second generators, 57 and 58, may be difficult. Under those circumstances, the third engine 13 and third generator 43 provide the additional current to maintain the charge level of the electrical storage device 40 at appropriate magnitudes.

FIG. 10 illustrates a mode operation of the present invention in which the operating conditions of the marine vessel 10 require not only the torque provided by the first and second engines, as represented by arrows 110 and 114, but the additional torque provided by the first and second motors, 53 and 54, of the motor-generators. The torque provided by the combination of the first and second engines, 11 and 12, and the first and second motors, 53 and 54, allows the marine vessel 10 to be driven at increased speeds and under increased loads. The house load 46 is powered by the electrical storage device 40 which also provides the necessary current, as represented by arrows 103 and 104, to drive the first and second motors.

FIG. 11 illustrates a mode which is generally similar to that described above in conjunction with FIG. 10, but with the additional use of the third engine 13 and the third generator 43 to provide electric power which is used to recharge and/or maintain the charge level of the electrical storage device 40. The first and second engines, 11 and 12, provide mechanical torque to drive the first and second marine propulsion devices, 21 and 22. In addition, torque is provided by the first and second motors, 53 and 54, that are energized by the electrical storage device 40 which also provides electric power to the house load 46. The first and second engines, 11 and 12, are combined with the first and second motors, 53 and 54, to provide torque to the first and second marine propulsion devices. All three engines, 11-13, are active in the mode illustrated in FIG. 11.

FIG. 12 illustrates the mode of operation in which the first and second engines are used to drive the first and second marine propulsion devices, respectively, and the house load is powered by the electrical storage device 40 with the third engine 13 and third generator 43 providing electric power to recharge or maintain the charge of the electrical storage device 40. The arrangement illustrated in FIG. 12 is generally similar to that illustrated in FIG. 7, but with the additional use of the third engine 13 and third generator 43 to maintain the charge of the battery system.

With continued reference to FIGS. 1-14, it should be understood that the various embodiments illustrated in FIGS. 1-12 provide different interconnections between the individual components of the system in order to achieve the desired results in many different circumstances of operation. The operating speed of the marine vessel and the load requirements are two of the variable parameters that can be used to determine the specific mode of operation. The ability to interconnect the engines, generators, motors, electrical storage device, and marine propulsion devices in these varied ways provides significantly improved flexibility and reduces the overall energy consumption of the marine vessel. In addition, the ability to use a single engine to provide power to both marine propulsion devices allows the engine to be operated at improved efficiency levels that would not be possible if two engines were used and operated at lower speeds and loads. In addition, this ability provides a significantly beneficial option if one of the two main engines is disabled. The ability to drive the two marine propulsion devices, 21 and 22, with both the internal combustion engines and electric motors allows increased speeds and loads to be achieved than would otherwise be possible if only the internal combustion engines were used.

With continued reference to FIGS. 1-15, the mode illustrated in FIG. 1 shows the house load 46 supported solely by the electrical storage device 40 which, in a particularly preferred embodiment of the present invention, comprises a series of battery cells which can be either wet cells or dry cells. The mode of operation illustrated in FIG. 2 is generally similar to that in FIG. 1, but with the use of the third engine 13 and third generator 43 to recharge or maintain the charge level of the electrical storage device 40 which powers the house load 46. FIG. 3 shows a mode of operation in which the two motor-generators, 31 and 32, are operated as motors, 53 and 54, to provide motive power to the first and second marine propulsion devices, 21 and 22. The electrical storage device 40 is used to provide electric power to the first and second motors and to the house load 46. FIG. 4 illustrates the mode of operation that is generally similar to that described above in conjunction with FIG. 3, but with the additional use of the third engine 13 and third generator 43 to recharge or maintain the charge of the electrical storage device 40. Similar to the embodiment shown in FIG. 3, the marine propulsion devices, 21 and 22, are provided with torque from the first and second motors, 53 and 54, which are, in turn, provided with power from the electrical storage device 40. FIG. 5 shows the use of a single engine to provide torque to both the first marine propulsion device 21 and the first generator 57 with the electrical storage device 40 providing electric power to the house load 46 and to the second motor 54 which drives the second marine propulsion device 22. As a result, the first marine propulsion device 21 is powered by the first engine 11 and the second marine propulsion device 22 is powered by the second motor 54. FIG. 6 is generally similar to FIG. 5, but with the additional use of the third engine 13 and third generator 43. As in the mode illustrated in FIG. 5, the first motor-generator 31 is operated as a generator and the second motor-generator 32 is operated as a motor. The embodiment of the present invention shown in FIG. 7 connects the first and second engines in torque transmitting association with the first and second marine propulsion devices by energizing the first and second clutches, 71 and 72, illustrated in other figures. The house load 46 is supported by the electrical storage device 40. FIG. 8 shows the first and second engines being connected to provide torque to both their associated marine propulsion devices and their associated generators, 57 and 58. The generators provided electric power to the electrical storage device 40 which, in turn, provides electric power to the house load 46. FIG. 9 is generally similar to FIG. 8, but with the additional use of the third engine 13 and third generator 43 to recharge and/or maintain the charge level of the electrical storage device 40. In FIG. 10, the marine propulsion devices are powered by their associated engines, 11 and 12, and by their associated motors, 53 and 54. The motors receive electric power from the electrical storage device 40 which also powers the house load 46. FIG. 11 shows a mode of operation that is generally similar to that illustrated in FIG. 10, but with the additional provision of electric power to the electrical storage device 40 by the third engine 13 and third generator 43. As in FIG. 10, the first and second marine propulsion devices, 21 and 22, are powered by the mechanical connection to the first and second engines, 11 and 12, and the first and second motors, 53 and 54. FIG. 12 illustrates a circumstance in which the first and second engines, 11 and 12, are connected mechanically to provide torque to the first and second marine propulsion devices while the third engine 13 and third generator 43 are used to provide electric power to the electrical storage device 40 which, in turn, provides power to the house load 46. The motor-generators are not directly involved in providing power to the electrical storage device 40 or in providing torque to the first and second marine propulsion devices, 21 and 22. FIG. 13 shows the basic components of a preferred embodiment of the present invention and FIG. 14 shows those basic components with additional representations of various electrical devices and systems used to interconnect those components. In addition, the first and second clutches, 71 and 72, are shown. FIG. 15 is a simplified section view of the first motor-generator 31 and the first clutch 71 connected between the output shaft 51 and the driveshaft 61.

It should be understood that several of the modes of use of preferred embodiments of the present invention benefit from the provision of a clutch in association with the forward, neutral, and reverse gears of the drive units, 21 and 22. The use of this clutch, in addition to clutches 71 and 72, is to facilitate and improve the efficiency of the generation of electric power when the motor/generators, 31 and 32, are driven by their respective engines, 11 and 12, to generator electric power. This clutch allows the drive units to be disconnected from the engines when electric power is being generated in this manner.

With continued reference to FIGS. 1-15, it can be seen that a marine vessel 10 made in accordance with a preferred embodiment of the present invention comprises a first engine 11, a first marine propulsion device 21 which is connectable in torque transmitting association with the first engine 11, a first motor 53 which is connectable in torque transmitting association with the first marine propulsion device 21, a first generator 57 which is connectable in torque transmitting association with the first engine 11, a second engine 12, a second marine propulsion device 22 which is connectable in torque transmitting association with the second engine 12, a second motor 54 which is connectable in torque transmitting association with the second marine propulsion device 22, and a second generator 58 which is connectable in torque transmitting association with the second engine 12. In a particularly preferred embodiment of the present invention, it further comprises an electrical storage device 40 which is connectable in electrical communication with the first and second generators, 57 and 58, and with the first and second motors, 53 and 54. The electrical storage device in a particularly preferred embodiment of the present invention comprises at least one dry cell or wet cell battery. The electrical storage device 40 is configured to receive electric current from the first generator 57, the second generator 58, or the third generator 43. The electrical storage device 40 is configured to provide electric current to the first motor 53 and the second motor 54. The electrical storage device 40 is configured to provide electric current to a house load 46 of the marine vessel 10. In a preferred embodiment of the present invention, it further comprises a third engine 13 associated with the third generator 43 which is, in turn, connectable in electrical communication with the electrical storage device 40. In a preferred embodiment of the present invention, a first motor-generator device 31 comprises the first generator 57 and the first motor 53 and a second motor-generator device 32 comprises the second generator 58 and the second motor 54. First and second clutches, 71 and 72, are configured to selectively connect the first and second engines in torque transmitting association with the first and second marine propulsion devices, 21 and 22, respectively. In certain modes of operation, the first engine 11 is connected in torque transmitting association with both the first marine propulsion device 21 and the first generator 57 while the second motor 54 is simultaneously connected in torque transmitting association with the second marine propulsion device 22. At the same time, the second engine 12 is disconnected from torque transmitting association with the second marine propulsion device 22.

Although the present invention has been particularly illustrated to show numerous embodiments and modes of operation and although the preferred embodiments of the present invention have been described with specificity, it should be understood that alternative embodiments are also within its scope. 

1. A marine vessel, comprising: a first engine; a first marine propulsion device, said first engine being connectable in torque transmitting association with said first marine propulsion device; a first motor, said first motor being connectable in torque transmitting association with said first marine propulsion device; a first generator, said first engine being connectable in torque transmitting association with said first generator; a second engine; a second marine propulsion device, said second engine being connectable in torque transmitting association with said second marine propulsion device; a second motor, said second motor being connectable in torque transmitting association with said second marine propulsion device; and a second generator, said second engine being connectable in torque transmitting association with said second generator.
 2. The marine vessel of claim 1, further comprising: an electrical storage device, said electrical storage device being connectable in electrical communication with said first and second generators, said electrical storage device being connectable in electrical communication with said first and second motors.
 3. The marine vessel of claim 2, wherein: said electrical storage device comprises a battery.
 4. The marine vessel of claim 2, wherein: said electrical storage device is configured to receive electric current from said first generator; said electrical storage device is configured to receive electric current from said second generator; said electrical storage device is configured to provide electric current to said first motor; and said electrical storage device is configured to provide electric current to said second motor.
 5. The marine vessel of claim 4, wherein: said electrical storage device is configured to provide electric current to a house load of said marine vessel.
 6. The marine vessel of claim 2, further comprising: a third engine; and a third generator, said third engine being connectable in torque transmitting association with said third generator, said electrical storage device being connectable in electrical communication with said third generator.
 7. The marine vessel of claim 1, wherein: a first motor-generator device comprises said first generator and said first motor; and a second motor-generator device comprises said second generator and said second motor.
 8. The marine vessel of claim 1, further comprising: a first clutch configured to selectively connect said first engine in torque transmitting association with said first marine propulsion device; and a second clutch configured to selectively connect said second engine in torque transmitting association with said second marine propulsion device.
 9. The marine vessel of claim 1, wherein: said first engine is connected in torque transmitting association with both said first marine propulsion device and with said first generator, said second motor being simultaneously connected in torque transmitting association with said second marine propulsion device.
 10. The marine vessel of claim 9, wherein: said second engine is disconnected from torque transmitting association with said second marine propulsion device.
 11. A marine vessel, comprising: a first engine; a first marine propulsion device, said first engine being connectable in torque transmitting association with said first marine propulsion device; a first motor, said first motor being connectable in torque transmitting association with said first marine propulsion device; a first generator, said first engine being connectable in torque transmitting association with said first generator; a second engine; a second marine propulsion device, said second engine being connectable in torque transmitting association with said second marine propulsion device; a second motor, said second motor being connectable in torque transmitting association with said second marine propulsion device; a second generator, said second engine being connectable in torque transmitting association with said second generator; and an electrical storage device, said electrical storage device being connectable in electrical communication with said first and second generators, said electrical storage device being connectable in electrical communication with said first and second motors, said electrical storage device being configured to receive electric current from said first generator, said electrical storage device being configured to receive electric current from said second generator.
 12. The marine vessel of claim 11, wherein: said electrical storage device is configured to provide electric current to said first motor; and said electrical storage device is configured to provide electric current to said second motor, said electrical storage device being configured to provide electric current to a house load of said marine vessel.
 13. The marine vessel of claim 11, further comprising: a third engine; and a third generator, said third engine being connectable in torque transmitting association with said third generator, said electrical storage device being connectable in electrical communication with said third generator.
 14. The marine vessel of claim 11, further comprising: a first clutch configured to selectively connect said first engine in torque transmitting association with said first marine propulsion device; and a second clutch configured to selectively connect said second engine in torque transmitting association with said second marine propulsion device.
 15. The marine vessel of claim 11, wherein: said first engine is connected in torque transmitting association with both said first marine propulsion device and with said first generator, said second motor being simultaneously connected in torque transmitting association with said second marine propulsion device.
 16. The marine vessel of claim 15, wherein: said second engine is disconnected from torque transmitting association with said second marine propulsion device.
 17. The marine vessel of claim 16, wherein: a first motor-generator device comprises said first generator and said first motor; and a second motor-generator device comprises said second generator and said second motor.
 18. A marine vessel, comprising: a first engine; a first marine propulsion device, said first engine being connectable in torque transmitting association with said first marine propulsion device; a first motor, said first motor being connectable in torque transmitting association with said first marine propulsion device; a first generator, said first engine being connectable in torque transmitting association with said first generator; a second engine; a second marine propulsion device, said second engine being connectable in torque transmitting association with said second marine propulsion device; a second motor, said second motor being connectable in torque transmitting association with said second marine propulsion device; a second generator, said second engine being connectable in torque transmitting association with said second generator; an electrical storage device, said electrical storage device being connectable in electrical communication with said first and second generators, said electrical storage device being connectable in electrical communication with said first and second motors, said electrical storage device being configured to receive electric current from said first generator, said electrical storage device being configured to receive electric current from said second generator, said electrical storage device being configured to provide electric current to said first motor, said electrical storage device being configured to provide electric current to said second motor; a third engine; and a third generator, said third engine being connectable in torque transmitting association with said third generator, said electrical storage device being connectable in electrical communication with said third generator.
 19. The marine vessel of claim 18, further comprising: a first clutch configured to selectively connect said first engine in torque transmitting association with said first marine propulsion device; and a second clutch configured to selectively connect said second engine in torque transmitting association with said second marine propulsion device.
 20. The marine vessel of claim 19, wherein: said first engine is connected in torque transmitting association with both said first marine propulsion device and with said first generator, said second motor being simultaneously connected in torque transmitting association with said second marine propulsion device when said second engine is disconnected from torque transmitting association with said second marine propulsion device. 